The purpose of this research is to define the role of social support systems in mitigating the effects of stress and affecting the use of primary care health services. The specific aims of the study include: (1) refinement of the definition and measurement of the concepts of stress and social support systems; (2) outlining the role of primary health care settings as a social support resource in response to people's social-psychological needs; (3) laying the groundwork for implementing experimental programs designed to work with and improve social support systems. We plan to accomplish the objectives through the use of a prospective research design that utilizes a multi-method approach, including personal interviews, daily diaries, telephone contacts, medical record reviews, and physician assessments. The results of the study will provide both a better understanding of the factors influencing the use of primary care health services, and insights into how these services can be organized to more effectively respond to stress, and thus increase people's health.